Improvement in dentists  rests



dotted States ateat dtititire.

'ROBE t" liINLltlY HUNT, OF WASHINGTON, DISTRICT OF COLUMBIA.

Letters Patent No. 109,411, dated November 22, 170; an'tedated November 5, 1870.

IMPROVEMENT IN DENTISTS RESTS.

The Schedule :deferred to in these Letters Patent: and making part of the same.

l, lonn'r ltrxLnr HUNT, ot' the city and county of \Vashington, in the DistrictI of Columbia, have invented an Adjustable t Dent-ists Rest or Support, of which the following is a specification.

Nature and Objects of the .lm-cultori.

The object of my invention is to provide a rest or support for thc body and arm ot.' dentists while operating on the teeth ot their patients, and thus avoid and prevent the great strain and thtig'u`e ot' the muscles heretotore 'consequent upon the stooping and constrained positions they are compelled to be, in, ,t'requently for a great length ot' time. To accomplish this I have provided cushions, one lor the body and one i'or the arm, to be attached to the. operating-chair, or fastened to the floor nearit, and capable, by suitable devices, ot' being so adjusted Fas to i'urnish a rest or support to the dentist in any required position,

Description oft/1e v.lecomprllying .iruniq Figure 1 shows the dentists rest attached to a chair.

Figure 2 shows in detail the, various part s mentioned, and designated by letters in the general description.

General leserilrm. Y

lhe whole apparatus .VormingI the dentists rest is attached to the operaiing-chair, as shown in the drawing, by staples ot' variable din-tensions, in which the bar B moves t'reely up and down, and can be iixed at any ,desired altitude luy-means ot' the clamp-screw working in the upper staple. .lhis bar l is made ot" steel, iron, brass, o1' othersuitable material, and is pretirably made hollow i'or stii'thess and lightness. ',lo prevent its turnt ing` in thc staples,it is -partially flattened throughout its length, except. two or three inches at the upper end,

which is lct't round, and its interior sin-tace tort-hat part, and concentric with it, is the eireular disk Ill, ,h also inadeot' suitable material, having its' outer edge provided with teeth or eogs, or their equivalent. A variable portionoithis disk may be cut out, andthe bar mayhehent at the, junction oi' the. ilattened and round parts, to suit' the shape ol' the. chair to which the rest is attached. f

'Ihc shat't' or stein S, made also ol' steel, iron, or other suitable material, has its upper part ilattened t'or about'- t.\vothirds ot" .its length, and the remainder round, with a beveled shoulder to the. round part where. it joins the flattened.' llhe lower or round part ot' the shaft S is madeso as to lit accurately and rotate i'reely in the upper 'or round parl. olf the bar I3, -t-he beveled shoulder on the t'ornier fitting in a countersink in the latter. A screw or other stop, projecting` through B into a grooved turned in S, near its lower any-desired point initsrotation. Y

ot'l adjustment is required, l enlarge the size otl the extremity, prevents its withdrawal trom B, except ai pleasure.

vC' is a. catch or stop, also of suitable material, made with aslot to tit accurately in width, but not in length, over the flattened part of the shaft: S.

Its outer end is provided with teeth or their equiv.- aient,` to tit into the teeth, cogs, or equivalent of the disk Il).

',Ihis outer end ot' the catch C has an apron, represented by the rod-1t, rigidly attached to it, which answers two purposes: one to keep the catch C in its proper relation tothe disk D, and the other to serve as a handle to operate thecatch. the catch (l is, by engagingits teeth or-cquivalent with the teeth, cogs,-or equivalent of thc disk D, to stop and retain the shaft S, with its attachments, at When greater nicety teeth or cogs in the disk 1),and equally the. spaces hetuecn them, and insert; in the outer end of the catch O, in lieu ot' the tecth,"a tangent-screw with a square thread to work in the enlarged teeth ot' thc disk.

Ihe slotted arm A, also ot'iron, steel, or other suitable material, is attached to and pivoted on the upper extension ot' the inner end ot' the slotted arm A, and y against the edge ot' the tiattened part of the shaft S. This is necessary on account ot the different inclination ot' dillbrent chairs, and the diterent inclination of the same chair when thrown back.

" the earth-:r it), also ot suitable material, sustaining the cushions, has a slot in it, through which a clampse-rcw, F, with a broad head, works, as well as through the slot in the arm A. The clamp-screw F has a thumb-uut at its lower end, and a train-washer, the sides ot which extend up, and by embracingl prevent the spreading ot'the sides of the slotted arm A. The carrier -E can bc moved in the. direction of the slot in it, as well as ot' the slot in the arm A, and can be rotated so as to place thc f 'acc oi the cushions it sustains in any required direct-ion.

lo one end ot' the carrier E is hinged a plate or bar, l, also ot' suitable. material, moving on the hinge in a vertical plane, and having rigidly attached to it, on the outside, in the middle, at right angles, a doublebeveled plate or slide, l, on which the body-cushion 0, by a suitable device, slides laterally.

On the inner side of the plate P, and longitudinally with it', is aratchet, H, with a double set ot` teeth.

Hinged t-o the other endof the carrier E is a mov- 'Ihc function otA able brace, M, which, by engaging the teeth of the lower set in the ratchet H, supports and retains the plate l, with the body-cushion O, at any desired inclination. p

l Attached to the upper end of' the plaie-P, by a bingo, and working in the saine vertical plane' as l and M, -is another slide, L, on which the arm-cushion N slides in the same vertical plane. Suitable stops, as shown in the drawing, prevent both these cushions from moving,r too far or coming off .the slides.

On the under side of the slide L is hinged a pawl,

lZ, which, by engaging the teeth of' the uw er set in' the ratchet H, supports and reta-ins the arm-cushion N at any desired inclination:

p Claims. Il claim as my invention- 1. The combina-tion of the bar B, the disk D., the shaft S, and arm A, the c-ateh C, the carrierv E,`the plate P, the cushion 0,:1nd the Aclamp-screw F, arranged and operated substantially as herein described.

2;v 'lhe adjustable dent-ists rest, herein described, consisting substantially of the bar B, the toothed disl 1), the shaft S, the catch C, the rod l, the arm A, the sereni- G,.the carrier E, the' clamp-screw F, the

fitnessesz l RVH. S. THQMI-sox, R. M. DAWES.

plate l, the slides K and L, the cushions U and N, 

